Sanitary spray nozzle for spray guns

ABSTRACT

An automatic spray gun incorporates threadless, sanitary couplings for all air and fluid flow path connections for less contamination and lower maintenance. The spray gun nozzle body has threadless connection inlet couplings for air and fluid supply lines. There are threadless connections between the fluid tip and the nozzle body and between the air cap and the fluid tip. The nozzle body/fluid tip connection may incorporate multiple passageways for air and fluid flow; for example a center passageway for fluid flow plus annular middle and outer passageways for atomizing air and fan air respectively, for which seals such as O-rings or a full face gasket may be incorporated at this interface. The nozzle body may also have a threadless connection coupling for the actuator. The actuator can be a conventional mechanism or a diaphragm sealed shut-off/clean out needle mechanism or such other mechanism as may be available, or may simply be a block off cap in applications where air and fluid flow are controlled externally.

This application relates and claims priority to U.S. applications Ser.No. 60/178,099 filed Jan. 26, 2000.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention most generally relates to automatic spray guns, both airatomizing and hydraulic pressure atomizing. In particular, it relates toautomatic spray guns incorporating non-threaded couplings between allmajor body components and air and fluid supply lines.

2. Background Art

Conventional automatic spray guns in general have a shut off needle thatseals on the back of a fluid tip or nozzle and an actuator to operatethe needle with interference seals or packing to seal the liquid beingsprayed. Conventional automatic spray guns also have threaded componentssuch as a fluid tip or nozzle, threaded connections and a threadedpacking retainer of some sort. Refer to prior art drawing FIG. 1,showing a conventional spray gun with a threaded air cap and threadedactuator cap, and threaded ports for inlet air and fluid lineconnections.

It has been standard procedure for many years in the food andpharmaceutical industries to use sanitary fittings wherever possible forvalves, pipes, filters and other components, to meet both practical andregulatory sanitation requirements for avoiding contamination by orduring the production process. Sanitary fittings generally consist offlanged joints having opposing flats that are abutted in a sealingfashion so as to minimize the potential for trapping trace amounts ofthe material in places that cannot be easily cleaned and inspected. Thejoints are secured for alignment and to hold against separation bypressure by mechanical means external to the seal.

In the past the use of threads has been allowed because of necessity.Automatic spray guns are complex fluid deposition nozzle mechanisms thathave undergone considerable engineering scrutiny and development tooptimize their performance for the many applications and fluids forwhich they are used. None the less, the use of internal threads hasgenerally been considered an acceptable design solution for couplingaperatured components together for pressurized applications such as thebody of the automatic spray gun. However, threaded pipe connections andcouplings are inherently unsanitary. Internal threads in an automaticspray gun allow the ready accumulation and growth of bacteria,eventually contaminating the fluid flow. Threaded connections requirefrequent, time-consuming rotary disconnection and reconnection, andcannot be easily cleaned, polished, or inspected.

Some gun manufacturers have welded sanitary inlet connections to thebody of the gun in an effort to provide sanitary connection ports forfluid and air line connections. In some cases the customer or user hasundertaken to rework a standard spray gun model to gain this feature,because the sanitary inlet connection was not available from themanufacturer. This still does not address the problem of the threadsthat hold the fluid tip in place and also the threads that hold the sealretainer in place.

Readers may find UK Patent GB2199288 and U.S. Pat. Nos. 5,379,938,4,348,040, 4,537,355, and 5,944,259, to provide useful context for abetter appreciation of the invention, a description of which follows.

SUMMARY OF THE INVENTION

It is an object of the invention to eliminate or to isolate with sealsthe prior art threaded couplings common to automatic spray guns. It is afurther object to improve the sanitary aspects of an automatic spray gunregarding use and maintenance, by eliminating threaded connections fromthe component parts. It is a yet further object to reduce the risk ofcontamination in the spray dispensing of fluids from automatic sprayguns. It is a still yet further object of the invention to provide aface to face coupling between a nozzle body and fluid tip in a spraygun, that accommodates and seals axial and multiple annular passageways.

To these ends, in accordance with the invention, there is an automaticspray gun incorporating threadless, sanitary connection couplings forall air and fluid flow path connections. The spray gun nozzle body hasthreadless inlet couplings for air and fluid supply lines. The gun alsohas a threadless connection coupling between the fluid tip and thenozzle body and between the air cap and the fluid tip. The nozzlebody/fluid tip coupling incorporates and seals, in some embodiments,multiple passageways for air and fluid flow such as a center passagewayfor fluid flow plus annular middle and outer passageways for atomizingair and fan air respectively.

The nozzle body also has a sanitary connection for the needle actuatoron the back end of the gun. The actuator can be a conventional mechanismor a diaphragm sealed shut-off/clean out needle mechanism or such othermechanism as may be available. The actuator may be omitted and theposition closed off with a threadless connection cap in applicationswhere air and fluid flow are controlled externally. Limited departuresfrom the all-sanitary connection couplings model can include threadedcap couplings for attaching the air cap and/or the actuator body, wherethe application requires accommodation of components still utilizingthreaded connections.

Still other objects and advantages of the present invention will becomereadily apparent to those skilled in this art from the followingdetailed description, wherein I have shown and described only apreferred embodiment of the invention, simply by way of illustration ofthe best mode contemplated by me on carrying out my invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section view of a prior art multi-fluid nozzleassembly with threaded couplings between body components and threadedinlet ports for air and fluid.

FIG. 2 is a cross-section view of a preferred embodiment of theinvention, sanitary connection couplings between all body components andsanitary connection nipples for air and fluid inlets.

FIG. 3 is a cross-section view of a preferred embodiment of theinvention, an automatic spray gun configured with a block off cap ratherthan an actuator, the cap being mated to the nozzle body with a sanitaryconnection coupling.

FIG. 4 is a face view of a clamp for a sanitary connection coupling, forholding the joint in axial alignment and sealed together againstinternal pressure.

FIG. 5 is a cross section view of a limited embodiment of the inventionutilizing threaded cap couplings to attach a diaphragm sealed actuatorto the nozzle body and the air cap to the fluid tip.

FIG. 6 is a cross section view of another limited embodiment of theinvention utilizing a threaded cap coupling for the air cap to fluid tipattachment and illustrated with a conventional sealed actuator attachedto the nozzle body with a sanitary connection coupling.

FIG. 7 is a cross section view of yet another limited embodiment of theinvention utilizing a threaded cap coupling for the air cap to fluid tipattachment and illustrated with a diaphragm sealed actuator attached tothe nozzle body with a sanitary connection coupling.

FIG. 8 is a cross section view of still yet another limited embodimentof the invention utilizing a threaded cap coupling for the air cap tofluid tip attachment and illustrated with a block off cap attached tothe nozzle body with a sanitary connection coupling.

FIG. 9 is a cross section view of even still yet another limitedembodiment of the invention having a back-angled fluid inlet andutilizing a threaded cap coupling for the air cap to fluid tipattachment and illustrated with a block off cap attached to the nozzlebody with a sanitary connection coupling.

FIG. 10 is a cross section view of elements of a preferred embodiment ofthe invention, an air cap and fluid tip combination attached by asanitary connection coupling, with the back side of the fluid tipconfigured with a sanitary connection coupling, and further illustratingthe O ring seal grooves for the axial and annular fluid and airpassageways.

FIG. 11 is a cross section view of a nozzle body of a preferredembodiment of the invention, equipped with sanitary connection couplingflanges front and back and on the air and fluid ports, furtherillustrating the interior channels from inlet ports to center andannular passageways through which air and fluid flow, and O ring groovesin the coupling flats of the inlets and front face of the nozzle body.

FIG. 12A is a face view of a gasket for sealing the air cap to nozzlebody joint of a preferred embodiment, with a center hole for fluid flowand multiple surrounding holes for air flow.

FIG. 12B is a cross section side elevation of the gasket of FIG. 12A,showing a raised bead structure of the gasket that is analogous to apair of O-rings that might be used in the alternative.

DESCRIPTION OF THE PREFERRED EMBODIMENT

To those skilled in the art, the invention admits of many variations. Anenabling description of the preferred embodiment follows.

As a preliminary matter, a sanitary connection coupling is defined hereas a non-threaded coupling system for joining pipe sections together orto hollow bodied or aperatured fittings or devices, or for joiningcomponents of such devices, such that the internal passageways are heldin alignment to enable through flow of air or fluid, and where theholding or clamping structure or mechanism is external of the joint sealand is sufficiently strong to withstand ordinary internal workingpressures. For example, the clamping mechanism or structure may be acommercially available channel clamp that clamps mating flanges intoaxial alignment and facial compression, or flange bolts applied throughmating flanges, or a slotted flange, partial rotation bayonet or luglock system, or any such non-threaded means as is known in the prior artor arises hereafter, for which the form factor is acknowledged as beingby industry standards more sanitary than conventional threadedconnections.

Referring back to Prior Art FIG. 1, it will be noted that the aircap/fluid tip component is coupled to the nozzle body by a threadedconnection , that the actuator housing is coupled to the nozzle body bya threaded connection, and that the inlets for fluids and atomizing airare likewise configured with threaded connections.

For the following description and remaining figures, couplings will becommonly referenced as a coupling 1, and their related component partswill be identified as coupling flanges 2, ring clamps 3, and seals orsealing features 4, although their exact features may vary from onefigure to another. A threaded cap coupling and all similar threadedcouplings will be referred to as threaded cap coupling 5.

Referring now to FIG. 2, there is a nozzle body 20 with a topside inletair port 21 configured with a coupling flange 2 and connecting toannular passageway 22, and a bottom side fluid inlet port 23 configuredwith a flange 2 and connecting to center passageway 24. Needle actuator25 is attached by a coupling 1 consisting of a ring clamp 3 or othersuitable fastening element (the ring clamps being omitted from severalof the other subsequently referred to figures for clarity) which securesrespective coupling flanges 2 face to face at the back end of nozzlebody 20. Air cap 27 is attached to fluid tip 26 by a similar coupling 1,which is attached to the front end of nozzle body 20 by another similarcoupling 1. The fluid tip 26, nozzle body 20 coupling 1 incorporatessealing features 4, in this case concentric O-rings located inrespective grooves in the faces of the joined components, to sealpassageways 22 and 24.

Referring now to FIG. 3, the needle actuator 25 is replaced by a blockoff cap 35, again attached to nozzle body 20 by a coupling 1, forapplications where external control of air and fluid flow is provided.FIG. 3 is otherwise identical to FIG. 2.

Referring to FIG. 4, a hinged, V groove, ring clamp 42 is a preferredembodiment example of the typical clamp 3 for the common coupling 1design appearing throughout the figures.

Referring to FIG. 5, a limited embodiment of the invention utilizesthreaded cap couplings 5 to attach a diaphragm sealed actuator 55 to thenozzle body 50 and the air cap 57 to the fluid tip 56. FIGS. 6-9 showother limited embodiments with threaded aircap couplings 5; FIG. 6having a conventional sealed actuator with clamp connection, FIG. 7having a diaphragm sealed actuator with clamp connection, FIGS. 8 and 9having a block off cap, and FIG. 9 illustrating an angled fluid port.These figures illustrate how the invention can accommodate various typesof actuators, including diaphragm sealed and conventionally sealedactuators, as well as other variations in design, all with a goal ofproviding sanitary connections wherever possible within the limits ofthe user's other requirements.

As is commonly known to those skilled in the art, and extends to theinvention, nozzle bodies may be variously configured for two or moreinlets. The inlets may or may not be in a common cross plane, relativeto the axis of the nozzle body, and may be variously configured asnormal or at a lesser angle as to the axis of the nozzle body. Forexample, there may be a nozzle body with four inlet ports for air andfluid in one plane, two on opposite sides of the body and two on thetopside, all configured with threadless, sanitary connection couplingflanges. As another example, a nozzle body may have two opposing air andfluid inlet ports in one cross plane, one port on top and one on thebottom, both configured with threadless, sanitary connection couplingflanges. Many other variations of inlet ports on a nozzle body arepossible.

Likewise, there are many variations and combinations of prior artthreaded connections and threadless connections that may be employed onan automatic spray gun that might be necessary to particular users inorder to optimize interchangeable parts or utilize existing inventory ofactuators or nozzles while moving towards full implementation ofnon-threaded, sanitary connections.

Referring to FIG. 10, there is shown an air cap 27 and fluid tip 26attached by a coupling 1, with the back end of fluid tip 26 having acoupling flange 2 for a coupling 1 with a nozzle body. Sealing feature 4is a pair of concentric O-ring grooves which will accept O-rings forsealing interior fluid passageways when fluid tip 26 is mated to thematching nozzle body of FIG. 11.

Referring to FIG. 11, there is shown the nozzle body 20 of FIGS. 2 and3, more clearly illustrating the topside inlet air port 21 configuredwith a flange 1 and connecting to annular passageway 22, and a bottomside fluid inlet port 23 configured with a flange 2 and connecting tocenter passageway 24. Flanges 2 and sealing features 4 are evident atthe inlets and front and back ends of the nozzle body.

Referring to FIGS. 12A and 12B, air passages 22 and fluid passage 24 maybe sealed by a sealing feature 4 gasket, shown here in front and crosssection views, configured with conforming holes for the passageways andraised ribs 4A to fit the interface grooves between fluid tip 26 of FIG.10 and nozzle body 20 of FIG. 11.

There are other and various embodiments within the scope of theinvention. For example, there is an automatic spray gun consisting of anozzle body, an actuator, a fluid tip, and an air cap, where the nozzlebody is configured with at least one air inlet and one fluid inlet,where each inlet has threadless means for connecting to a respective airor fluid supply line. The nozzle body and fluid tip are configured witha threadless means for interconnection, the fluid tip and air cap areconfigured with a threadless means for interconnection, and the nozzlebody and actuator are configured with a threadless means forinterconnection.

As a variation to the above example, there is an automatic spray gun asabove, where the nozzle body and fluid tip have mating faces, and themating faces have matching openings for central and annular passagewaysfor fluid and air flow, where the respective openings are aligned andthe passageways are sealed from leakage upon interconnection of thenozzle body to the fluid tip.

As a further variation on the above example, the passageways may besealed by O-rings in O-ring grooves in the mating faces, or by a gasketfitting the face and grooves, with openings to accommodate thepassageways. The O-ring or gasket or other sealing feature may be heldin compression by the ring clamp on the coupling flanges by which thenozzle body and fluid tip are held together.

As another example, there is a nozzle body and mating fluid tip for anautomatic spray gun, where the nozzle body is configured with at leastone air inlet and one fluid inlet, each inlet having a threadlessconnector flange suitable for connection with a conforming ring clamp toa respective air or fluid supply line configured with a matingthreadless connector flange, and where the nozzle body and fluid tip areeach configured with mating threadless connector flanges so as to beinterconnectable at the flanges with a conforming ring clamp.

As a variation on the above example, there is in addition to the nozzlebody and fluid tip, an air cap, where the fluid tip and the air cap areeach configured with threadless connector flanges and areinterconnectable by means of a ring clamp.

As another variation on the above example, there is in addition anactuator, where the nozzle body and the actuator are configured withthreadless connector flanges and are interconnectable by means of a ringclamp.

As will be realized, the invention is capable of other and differentembodiments, and its several details are capable of modifications invarious obvious respects, all without departing from the invention. Thefollowing claim or claims are illustrative but not exhaustive of thescope of the invention disclosed.

I claim:
 1. An automatic spray gun comprising a nozzle body, anactuator, a fluid tip, and an air cap, said nozzle body configured withat least one air inlet and one fluid inlet, each said inlet having athreadless coupling for connecting to a respective air or fluid supplyline, said nozzle body and said fluid tip having a threadless couplingfor interconnection, said fluid tip and said air cap having a threadlesscoupling for interconnection, and said nozzle body and said actuatorhaving a threadless coupling for interconnection.
 2. The automatic spraygun of claim 1, said nozzle body and said fluid tip having mating faces,said mating faces comprising matching openings for central and annularpassageways, respective said openings being aligned and said passagewaysbeing sealed from leakage upon said interconnection of said nozzle bodyto said fluid tip.
 3. A nozzle body and mating fluid tip for anautomatic spray gun, said nozzle body configured with at least one airinlet and one fluid inlet, each said inlet comprising a threadlessconnector flange suitable for connection with a conforming ring clamp toa respective air or fluid supply line configured with a mating saidthreadless connector flange, said nozzle body and said fluid tip eachconfigured with said threadless connector flanges and beinginterconnectable there at with a said conforming ring clamp.
 4. A nozzlebody and mating fluid tip for an automatic spray gun according to claim3, said nozzle body and said fluid tip having mating faces, said matingfaces comprising matching openings for central and annular passageways,respective said openings being aligned and said passageways being sealedfrom leakage upon an interconnection of said nozzle body to said fluidtip.
 5. A nozzle body and a fluid tip for an automatic spray gunaccording to claim 3, further comprising an air cap, said fluid tip andsaid air cap each configured with said threadless connector flanges andbeing interconnectable by means of a said ring clamp.
 6. A nozzle bodyand a fluid tip for an automatic spray gun according to claim 3, furthercomprising an actuator, said nozzle body and said actuator configuredwith said threadless connector flanges and being interconnectable bymeans of a said ring clamp.
 7. An automatic spray gun comprising anozzle body, an actuator, a fluid tip, and an air cap, said nozzle bodyconfigured with at least one air inlet and one fluid inlet, each saidinlet comprising a threadless connector flange suitable for connectionwith a conforming ring clamp to a respective air or fluid supply lineconfigured with a mating said threadless connector flange, said nozzlebody and said fluid tip each configured with said threadless connectorflanges and being interconnectable there at with a said conforming ringclamp, said fluid tip and said air cap each configured with saidthreadless connector flanges and being interconnectable by means of asaid ring clamp, and said nozzle body and said actuator configured withsaid threadless connector flanges and being interconnectable by means ofa said ring clamp.
 8. The automatic spray gun of claim 7, said nozzlebody and said fluid tip having mating faces, said mating facescomprising matching openings for central and annular passageways,respective said openings being aligned and said passageways being sealedfrom leakage upon said interconnection of said nozzle body to said fluidtip.
 9. The automatic spray gun of claim 7, said passageways beingsealed by O-rings.
 10. The automatic spray gun of claim 7, saidpassageways being sealed by a gasket.